Clade Ecdysozoa-Molting Animals Ecdysis- “an escape” -molting of exoskeleton or cuticle Phyla- Nematoda and Arthropoda

Phylum Nematoda Nematodes: roundworms Nemata- “ thread” Bilateral symmetry Tube within a tube structure-mouth and anus 3 germ layers w/ pseudocoelom Smaller than flatworms, taper at both ends

Pseudocoelomate Ectoderm Mesoderm Endoderm Fluid filled cavity between the endoderm and ectoderm- pseudocoelom Differs from a true coelom because…. It is not entirely lined with mesoderm tissue Organs are not suspended or attached to membranes (mesenteries)

Lifestyle Thick outer covering (cuticle) to protect them from harsh environment ex. Stomach acid Move bodies with thrashing motion MOST Free living-Decomposers and predators (tremendously abundant) SOME Parasitic- ex. Ascaris, hookworm, heartworm-host is dog Sexually reproduce: most are separate sexes some species are hermaphrodites

Nematodes Found everywhere Soil Oceans Polar ice Hot springs Parasites of nearly all plant and animal species!

Body Systems No Respiratory or Circulatory Systems- limits size of worm due to distribution of nutrients via osmosis and diffusion Complete Digestive Nervous Muscular Excretory Reproductive

Digestive System Complete Digestive Tract- Mouth Pharynx Intestine anus

Muscular System Longitudinal muscles only creates thrashing movement

Nervous System Nerve ring – “brain” Dorsal and ventral nerve cords

Excretory System Excretory cells Ducts pores

Nematode Reproductive Systems Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Nematode Reproductive Systems

Dioecious- separate sexes

Which is female?

Life cycles of parasitic roundworms ASCARIS lives in intestines and feeds off blood ingest eggs from dirty hands or unwashed veggies contaminated with fecal matter eggs hatch in intestines and enter bloodstream larval worms bore into lungs, must be coughed up and swallowed move to intestines where they mature Animal planet.com-Baylisascaris, brain eating parasite

TRICHINELLA bore into muscles causing painful cysts or live in intestines ingest cysts in undercooked/raw meat (usually pork) cysts open up in intestines and reproduce there Animal planet- “worms borrow through flesh”

HOOKWORMS lives in intestines feeds on blood, causes major damage to intestines eggs deposited on soil from contaminated wastes larvae live in soil burrow into feet or exposed skin of host larvae travel through bloodstream, to lungs, coughed up, swallowed attach to intestinal wall where they mature Ap.com- “flesh eating hookworm”“worms crawling under my skin”

PINWORMS most commonly infects children lives in intestines ingest eggs from contaminated soil or sand hatch in intestines female lays eggs near anus at night causing severe itching

Wuchereria bancrofti Lives in lymphatic system Vector- mosquito Daytime-worms in lungs Night-move to skin Obstruct lymph to cause swelling Mild- Filariasis Severe- Elephantiasis

Elephantiasis Ap.com- “Parasite causes elephantiasis” “40 year parasite”

Life Cycle of Wucheria spp. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Life Cycle of Wucheria spp. Fig. 11.15 11-13 Source: Redrawn From Centers for Disease Control, Atlanta, GA.

Loa loa Eye worm River blindness 2nd leading cause of blindness Vector- deer fly or black fly Ap.com- “river blindness”, “worms in my eye” https://www.youtube.com/watch?v=nkEkDHOQTLs

Dracunculus medinesis Fiery serpent Water contaminated with copepods carrying larva Females migrate towards legs Juveniles form blisters and exit via skin

Dirofilaria immitis Dog heart worm

The End